Various advanced driver assistance systems incorporate visual, acoustic, and/or sensor warnings. Many of these warnings are in response to outside dangers (e.g., proximity of another object). However, in recent times, the number of potential distractions for a driver has increased (e.g., mobile phones, mp3 players, internal displays, etc.). Occupant monitoring systems (e.g., driver monitoring systems, operator monitoring systems) are becoming more popular for inclusion in vehicles, such as, to warn when the driver is detected to be in a non-alert state.
In various implementations, an occupant monitoring system (OMS) includes a camera module (e.g., imaging unit, camera assembly) with a field of view directed toward a cabin of the vehicle, such as in the direction of one or more occupants in the vehicle. The field of view may be configured to encapsulate an expected position of the occupant. The OMS also includes one or more processing units in electrical communication with the imaging unit that receives and processes an image signal from the camera module to determine an occupant state and, in some implementations, provide feedback (e.g., output) based on the determined occupant state. An implementation of the type of the OMS described above is further detailed in U.S. Pat. No. 9,533,687, entitled “Occupant Monitoring Systems and Methods,” which is incorporated herein by reference in its entirety.
In prior implementations, the circuitry for the imaging and processing were disposed on distinct printed circuit boards (PCBs), in part, due to the alignment requirements for imaging the occupant. One such prior implementation is shown in Figure (FIG. 1.
FIG. 1 illustrates a side view of a camera module 101 for an OMS. The camera module includes circuitry for imaging 102 and circuitry for processing 103 connected by way of a flexible cable 104. A housing 105 supports and positions the imaging circuitry 102 to point in the direction 106 of one or more occupants in the vehicle.
In some implementations, the circuitry for imaging, circuitry for processing, and the flexible cable are fabricated using a rigid-flex circuit. Rigid flex circuits eliminate the need for a flexible cable by utilizing a flexible circuit layer bonded within the layers of two or more rigid multilayer circuits to form a flexible connection between the two or more rigid circuit boards. The flexible connection allows for the circuit boards to be positioned at an angle to one another. This approach is more convenient than attaching the boards by a flexible cable but suffers from added fabrication complexity and cost.
A need, therefore, exists for a camera module that (i) includes the imaging circuitry and processing circuitry incorporated on the same rigid circuit board and (ii) maintains a compact package size while still accommodating the positioning requirements for capturing an image of the vehicle occupant.